Depression is the most common neuro-psychiatric disorder found in patients with Parkinson's Disease (PD). It causes immense personal suffering, and is associated with increased disability and caregiver burden. Despite the adverse consequences of depression in patients with PD, there are virtually no empirical data to guide clinical treatment. In the absence of data, the SSRIs are apparently used as the first-line treatment, despite concerns about efficacy, safety, and tolerability in this population. This proposal is for a pilot study to establish the feasibility of, and generate sufficient data to plan, a larger clinical trial that will be able to inform clinical treatment of these patients. This pilot trial will (AIM 1) examine the feasibility of a larger trial, and establish (AIM 2) the effect size for short-term efficacy of anti-depressants, compared to placebo, in this population. It will also (AIM 3) evaluate the effect of long-term depression treatment on quality-of-life. This will be done in the context of a placebo-controlled, double-blind, parallel group, flexible dose trial of an SSRI (Paroxetine), a tri-cyclic (Nortriptyline) and placebo in acute (8 weeks) and long-term treatment (6 months). A total of 75 patients with PD (without significant motor fluctuations or Dementia) and depression (major depression or Dysthymia) will be randomized to each of the three arms in a balanced design. The feasibility issues that will be explored include recruitment, retention, drug tolerability, and the ability to maintain the blind. The outcomes that will be explored for the acute phase include changes in the Hamilton Depression Rating Scale (HAM-D) score, and the percent of patients who are responders (>50% improvement in the HAM-D, or < 10 on the HAM-D). The outcome variables explored for the long-term phase include the Parkinson's Disease Questionnaire and the Medical Outcome Study Short Form. Secondary analyses will involve the exploration of anxiety, motor disability, sleep, cognition, and individual or clusters of symptoms that are responsive to treatment in order to facilitate planning a subsequent, full-scale clinical trial. [unreadable] [unreadable]